The research is directed toward analyses and remediation of cognitive and linguistic process of mentally retarded persons. Studies are being conducted in both laboratory and natural settings. One series of projects is investigating the generalization of trained language skills to the natural environment, deinstitutionalization, and the prevention of institutionalization. Recently the investigators have analyzed variables which quantify differences in the conversational skills of retarded and non-retarded adults. Additional research is currently being conducted to remediate the conversational deficiencies of the retarded. A second series of studies is directed toward analyses of conceptual organizations, the relationship of the nonlinguistic conceptual organization to language acquisition, and the integration of various symbolic skills with existing knowledge. Recent investigations with nonverbal, severely retarded persons have shown that demonstration of visual discrimination among objects and among life-size, full-color photographs of the objects is not sufficient for demonstrating use of pictures to represent the objects. Investigators of a third series of studies are taking an information-processing approach for analyses and remediation of higher intellectual skills, specifically executive functioning and processing semantic information. These investigators are currently conducting studies assessing the cross-task validity of executive functioning.